as in treacherous
formal
causing harm in a way that is gradual or not easily noticed
Most people with this insidious disease have no idea that they are infected. an insidious enemy
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Example Sentences
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Recent Examples of insidious
This in our view is the insidious threat social media and rapidly growing AI capabilities pose to society and culture.
—
The Editorial Board, Chicago Tribune, 31 Aug. 2025
Never has fandom looked so intriguingly insidious.
—Michael Cuby, Them., 27 Aug. 2025
Habitat loss has been insidious — croplands have been stripped of their bordering hedgerows and old fields and woodlots have been converted to housing developments.
—Bruce Beehler, Baltimore Sun, 17 Aug. 2025
The simplicity of the scheme What made the fraud so insidious was its simplicity.
—Erik Lie, Fortune, 17 Aug. 2025
See All Example Sentences for insidious
The Editorial Board, Chicago Tribune, 31 Aug. 2025
Never has fandom looked so intriguingly insidious.
—Michael Cuby, Them., 27 Aug. 2025
Habitat loss has been insidious — croplands have been stripped of their bordering hedgerows and old fields and woodlots have been converted to housing developments.
—Bruce Beehler, Baltimore Sun, 17 Aug. 2025
The simplicity of the scheme What made the fraud so insidious was its simplicity.
—Erik Lie, Fortune, 17 Aug. 2025
See All Example Sentences for insidious
Recent Examples of Synonyms for insidious
Adjective
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Equipment and supplies were transported to and from the site using 4x4 vehicles in what were treacherous driving conditions, per the UWFRA.—
Escher Walcott,
PEOPLE,
6 Oct. 2025
-
Earlier, the company stressed that the rugged Oshkosh Defense Palletized Load System (PLS) M1075A1 excels in extreme conditions, efficiently distributing supplies and equipment in treacherous environments using demountable flat rack cargo beds or ISO containers.—
Prabhat Ranjan Mishra,
Interesting Engineering,
5 Oct. 2025
Adjective
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Though the Lions’ offensive linemen do an excellent job of selling run on play-action passes, there’s still a subtle difference to note early between run blocking and pass blocking.—
Jesse Newell,
New York Times,
11 Oct. 2025
-
There’s subtle tang from the sour cream and cream cheese.—
Jasmine Smith,
Southern Living,
11 Oct. 2025
Adjective
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In his plea agreement, Jones admitted using his company to submit more than $2 million in false bills to the Foundation for audiovisual services.—
Michelle Marchante,
Miami Herald,
12 Oct. 2025
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If convicted of bank fraud or making false statements, the penalties could include up to 30 years in prison and $1 million in fines for each count, the DOJ says.—
Deputy News Editor,
MSNBC Newsweek,
11 Oct. 2025
Adjective
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Unboxed, these black silicone bands look unassuming, but their simplicity is deceptive.—
Laura Paddison,
CNN Money,
7 Oct. 2025
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The shuttering of the agency that enforces laws against anticompetitive and deceptive business behavior is one small part of the national gridlock that began on Wednesday and could result in the furlough of 750,000 federal workers and delay air travel.—
Reuters,
USA Today,
2 Oct. 2025
Adjective
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Her Ashley is the movie’s fourth and fifth wheel, dismissed as both a perfidious troublemaker and a New Age airhead—a life coach in need of a wife coach.—
Justin Chang,
New Yorker,
22 Aug. 2025
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This perfidious situation, unintentional as its creation may have been, was strongly critiqued as far back as 1983 by Jonathan Crush and Paul Wellings in an article in The Journal of Modern African Studies.—
The Editors,
JSTOR Daily,
15 Aug. 2025
Adjective
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Boxer, a co-editor of the new book The Future of Youth Violence Prevention, insists that the larger premise of youth violence increasing is incorrect, as a variety of indicators indicate the overall problem in aggregate is on a steady decline over the last several years.—
John Scott Lewinski,
The Washington Examiner,
10 Oct. 2025
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The letter said the school district restructured its bonds, similar to refinancing a mortgage, and stated the city’s figure of $14 million in state funds was incorrect.—
Elizabeth Campbell,
Fort Worth Star-Telegram,
9 Oct. 2025
Adjective
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Surely, that will rub some the wrong way, but the Tide have now beaten three teams that haven’t lost to anyone else in Georgia, Vanderbilt and Missouri.—
Ralph D. Russo,
New York Times,
12 Oct. 2025
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The desire behind the making of the series was to right that wrong.—
Jesse Whittock,
Deadline,
12 Oct. 2025
Cite this Entry
“Insidious.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/insidious. Accessed 13 Oct. 2025.
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